1. Field of the Invention
The present disclosure relates to flat panel source driver integrated circuits, and more particularly, to shifter circuits for a flat panel source driver.
2. Description of the Related Art
Flat panels of liquid crystal displays (LCDs), for example, have become larger with the development of LCD technology. Accordingly, chip size and current consumption of source drivers for LCD flat panels have also increased.
FIG. 1 is a block diagram of a conventional flat panel source driver. A 6-bit source driver is shown in FIG. 1. Referring to FIG. 1, the source driver includes a multi-level shift circuit 11 for receiving data D<5:0> with a low voltage and complementary data DB<5:0>, and converting the levels of the data. The multi-level shift circuit converts the voltage of the data, and generates output data 0<5:0> with high voltage. A decoder 13 decodes the output data 0<5:0> of the multi-level shift circuit 11 in response to control signals C1 through C64, and a buffer 15 buffers the output of the decoder 13 and outputs display data OUT.
FIG. 2 is a circuit diagram of the multi-level shifter circuit 11. Referring to FIG. 2, the conventional multi-level shifter circuit 11 includes six level shifters 21 through 26. The six level shifters 21 through 26 each receive a corresponding bit of the data D<5:0> and a corresponding bit of the complementary data DB<5:0>, convert the level of the bits of data D<5:0> and the complementary data DB<5:0>, and generate the output data 0<5:0>. The level shifters 21 through 26 each include four PMOS transistors, such as P1B, P2B, P3B, and P4B for the level shifter 22, and two NMOS transistors, such as N1B and N2B for the level shifter 22.
Generally, a source driver includes thousands of conventional multi-level shifter circuits 11. Therefore, the source driver including the conventional multi-level shifter circuits 11 has a large chip size and consumes a large amount of current.